1. Field of the Invention
The present invention relates to a liquid crystal display, and particularly to a means for driving a liquid crystal display which is capable of decreasing crosstalk and which is suitable for obtaining a high quality display.
2. Description of the Related Art
Conventional liquid crystal matrix displays use, as a driving voltage to be applied to a single pixel, the voltage difference between the voltages applied to each X electrode and each Y electrode.
One of such driving methods is the optional bias driving method disclosed in Japanese Patent Publication No. 57-57718. The driving circuits used for realizing the driving methods are disclosed in Japanese Patent Laid-Open Nos. 53-38935, 58-176694, 60-21273 and 61-176694 and Japanese Patent Publication No. 61-51774.
In the conventional methods, it is assumed that both of the front edge and rear edge of a driving pulse have a clear right-angled shape. However, the actual waveform of the driving voltage applied to a single pixel is distorted by the load applied during driving and depends upon the content displayed. This consequently causes the occurrence of variations in brightness and of crosstalk in a screen even when the same information is displayed. The crosstalk creates an undesirable dark and light pattern in the screen, and particularly hinders to realization of a high quality display having a large area.
It is an object of the present invention to provide a liquid crystal display which is capable of decreasing variations in the effective values of the driving voltages respectively applied to pixels, which depend upon the content displayed on a liquid crystal panel, decreasing crosstalk and obtaining uniform brightness.